The loss of a bicycle to theft is an economic loss as well as a substantial inconvenience to the now-stranded cyclist. The loss of a favorite, customized or bicycle of exotic manufacture can also represent a substantial emotional loss from the time and energy associated with selecting just the right combination of features for the rider.
A number of anti-theft devices have been proposed that are intended to secure a bicycle or motorcycle and thereby prevent or impede theft. See, e.g., U.S. Pat. Nos. 3,747,376; 3,908,414; 5,092,142; 5,475,993; 5,487,285; 5,732,577; 5,913,906; 6,820,448; 7,437,898; 7,481,084; 7,712,339; 8,621,898; 8,881,559; US 2014/036233; and U.S. Pat. No. D579,756.
Despite such devices, those individuals with intent continue to find methods and techniques to defeat such anti-theft devices. Many of those techniques include the use of a handheld bolt cutter with hardened cutting jaws, a portable angle grinder or even a conventional hacksaw to cut through the antitheft device. Such cutters fail the target material in tension, but they induce the tension via the lateral component of the wedge-shaped blades. This means that a bolt cutter is a battle between the compressive strength of the cutting blades versus the compressive strength of the locking device. If both have near-equal hardness, it is difficult to predict which one will win. The battle becomes one of the quantum of pressure that can be applied on the device by the cutting jaws.
Typical, commercially available bolt cutters exhibit hardened blades of about 62 HRC and can cut 6 mm 48 HRC wire but only HRC 19 rods of 11 mm. This means why traditional chains of interlinked, connected wire stock, even if hardened and/or made of unique alloys, must be made so large and heavy: the bolt cutter acts on the individual wire stock diameter, not the overall chain width.
Surveillance videos show that members of the public rarely question or interfere with a thief in the act of breaking or cutting through a bicycle locking device, even when obviously using a bolt cutter or cut-off saw. Thus, cyclists cannot rely on help from passersby who might witness acts of theft in progress. The locking device must do more than just buy time—it must actually work.
It would be desirable to have an anti-theft device that was made from a material that could not be cut, melted, ground or drilled with handheld tools.
Some antitheft devices, such as the popular U-shaped devices, are defeated because they are large enough to secure only one wheel and the bike frame to a support. This leaves the other wheel vulnerable to removal and theft unless two such devices are carried and used together. This would double the cost and inconvenience of securing a bicycle against theft.
It would be desirable to have an anti-theft device that was sufficiently long in reach to secure both wheels and the frame to a stationary support.
Many locking systems are designed with a plurality of flat leg segments joined at a riveted joint that allows one leg segment to rotate and stack closely with the adjacent segments so as to fold into a compact unit that can be stored in a seat bag or on a frame clip. Such design considerations are visually appealing to consumers because they are easy to carry. Unfortunately, all of the currently known designs of this type are made from some version of steel, hardened steel or hard aluminum.
While titanium may have been suggested for bicycle locks (see, e.g., US Patent Publication Nos. 2014/0109631 and 2014/0260439), no specific grade or type of titanium is specified.
Titanium is available in various grades, based on the material properties. Commercially pure titanium is available in increasing hardness from Grade 1 to grade 4. These grades of titanium can be formed, engraved with conventional machines, and cut so that they can even be used as rings and similar jewelry. Stronger grades of titanium are alloys that have been mixed with one or more Group III-Group VIII materials (e.g., vanadium, molybdenum, nickel, ruthenium, palladium, chromium, zirconium, molybdenum, and aluminum) to increase their hardness. Sometimes referred to as “aircraft grade” titanium alloys, such materials are so hard that they are almost impossible to engrave, form or cut.